Presently, many terminals are provided with buttons. The buttons only have button function, and can be only used to close or cut off a circuit to achieve an instruction transmission function. The buttons have a single function, and take too much structural space of the terminals. Furthermore, presently, many terminals not only need buttons, but also need a power access function or a power output function, or a data input function and a data output function. For example, the terminals may be mobile phones, computers, mobile power packs, mobile storage devices, and so on. Generally, the terminal may be provided with a universal serial bus (USB) interface which may be used to transmit both power and data. However, it is usually complex to have an interface like the USB interface to be provided on the terminal, the space of the terminal is occupied, and the appearance of the terminal is also affected. Moreover, the interface is exposed to the outside of the terminal, thus dust or impurities are easy to enter the inside of the terminal, which affects the service life of the terminal. However, at present, no button structure can both meet requirements of various functions of the terminal and also save the structural space of the terminal.